1. Field of the Invention
The present invention relates to a substrate drying apparatus for dipping a substrate such as a semiconductor wafer, a glass substrate for a photomask or a liquid crystal display or a substrate for an optical disk (hereinafter simply referred to as a substrate) in a processing bath storing a processing liquid for processing the same and drying the substrate taken out from the processing bath by locating the same in an atmosphere containing vapor of a solvent, a substrate processing apparatus comprising the same and a substrate drying method.
2. Description of the Background Art
In a conventional substrate cleaning/drying apparatus for cleaning and drying a substrate, a processing bath is provided in a processing chamber for storing deionized water and dipping the substrate therein, so that the substrate is thereafter pulled up from the processing bath into an atmosphere containing IPA vapor (isopropyl alcohol vapor) while blowing the IPA vapor downward from a supply nozzle provided on an upper portion of the processing chamber with carrier gas of N2 and the IPA is condensed with respect to the deionized water adhering to the substrate surface, thereby removing the deionized water and processing residues contained therein and drying the substrate.
In order to condense the IPA on the substrate surface, the IPA vapor is set at a temperature higher than that of the deionized water, which is at the ordinary temperature.
In the aforementioned conventional apparatus, however, the IPA vapor is supplied into the closed processing chamber while taking out the substrate from the processing bath. Thus, it is difficult to excellently remove the water and the processing residues from the overall surface of the substrate.
Although it is important to condense the IPA vapor on the overall surface of the substrate as evenly as possible in order to remove the water and the processing residues adhering to the substrate surface, the IPA vapor may form a current in the closed chamber when blown into the closed chamber while taking out the substrate in the aforementioned conventional apparatus. Thus, the condensed part of the IPA vapor may be biased on the substrate surface or the amount of the condensed IPA vapor may be irregular. If the IPA vapor is partially uncondensed or the amount of the condensed IPA vapor is small, the water and the processing residues partially remain on the substrate surface and dried as such to deteriorate the quality of the substrate or cause particles in a subsequent step.
Further, the IPA vapor supplied at a high temperature is readily dissolved in the deionized water stored in the processing bath, to disadvantageously increase IPA consumption.
Although the substrate is taken out from the processing bath after the same is sufficiently cleaned, particles may adhere to the substrate.
Further, the concentration of the IPA vapor in the atmosphere of the processing chamber must be increased to approach a saturated state, leading to requirement for a large amount of IPA.
An apparatus for drying a substrate according to a first aspect of the present invention comprises a processing bath for storing a processing liquid, a chamber for storing the processing bath, solvent supply means for supplying vapor of a solvent into the chamber, handling means for pulling up the substrate from the processing bath, liquid supply means for supplying a processing liquid into the processing bath, and temperature control means for maintaining the processing liquid at a predetermined temperature which is lower than the ordinary temperature.
The temperature of the atmosphere containing the vapor of the solvent may not be increased beyond necessity in consideration of temperature fluctuation of the processing liquid, whereby safety can be improved while maintaining drying performance. Further, the amount of the solvent dissolved in the processing liquid may be small, whereby consumption of the solvent can be suppressed and the drying efficiency can be improved. In addition, the dissolved solvent hardly comes into contact with the surface of the substrate dipped in the processing liquid, whereby generation of particles can be suppressed.
The substrate can be dried by supplying the vapor of the solvent at the ordinary temperature with no heating to a high temperature, whereby the safety can be further improved while maintaining the drying performance. Further, the amount of the solvent dissolved in the processing liquid stored in the processing bath may be further reduced, whereby generation of particles can be further suppressed.
According to a second aspect of the present invention, the processing liquid is a cleaning liquid.
A layer of the solvent vapor of required concentration can be formed around the liquid level of the processing liquid even if no gas containing the solvent vapor is supplied toward the liquid level of the processing liquid, the amount of the solvent vapor dissolved in the processing liquid is reduced and the amount of supply of the solvent vapor is small, whereby the drying efficiency can be improved and consumption of the solvent can be further suppressed. Further, no gas containing the solvent vapor is supplied toward the liquid level while the amount of the supplied solvent vapor is small, whereby the amount of the solvent dissolved in the processing liquid is reduced. Thus, generation of particles can be suppressed by dipping the substrate in the processing liquid containing a small amount of solvent dissolved therein.
A first object of the present invention is to provide a substrate drying apparatus having excellent drying efficiency.
A second object of the present invention is to provide a substrate drying apparatus suppressing consumption of a solvent and generation of particles.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.